Evaluating the variability of aquatic acidification and photochemical ozone formation characterization factors for Canadian emissions

Background, aim, and scope  The Canadian life cycle impact assessment method LUCAS proposes a characterization of the impact categories aquatic acidification and photochemical ozone formation using a resolution scale based on 15 terrestrial ecozones. Each ecozone represents areas of the country which can be identified easily by general living (biotic) and nonliving (abiotic) characteristics. The three main purposes of this research are to improve the characterization models of both impact categories including regional exposure and effect factors, to investigate what is the best resolution scale between Canadian provinces or ecozones, and to analyze the extent of spatial variability. Materials and methods  A model framework accounting for variability in fate, exposure and effect factors has been elaborated. The same fate factor, based on Advanced Statistical Trajectory Regional Air Pollution matrices, applies to both impact categories. For the aquatic acidification impact category, the fate factor also accounts for the fraction of the deposition transferred to the aquatic ecosystem. The exposure factor for this impact category is considered to be 1 and the effect factor is based on the critical load exceedance, where the potential impacts are only considered in provinces or ecozones in which the critical load is exceeded. For the photochemical ozone formation impact category, the exposure factor is considered to be proportional to the population density in each province or ecozone, and the effect factor is represented by the chemical reactivity estimated with the maximum incremental reactivity model. The calculation of the new characterization factors using both a province-based and ecozone resolution scale was performed using a matrix which converts data from one resolution scale to another. Results  Results with the inclusion of the effect and the exposure factors show that the spatial variability between provinces remains within a factor of 10 and 5 for aquatic acidification and photochemical ozone formation, respectively. Discussion  Analysis of the results show that regionalization by province is preferable to regionalization by ecozone. It is more accurate in regard to atmospheric modeling and more representative of population distribution. However, averaging the fate factor and the population density over a whole province results in a serious limitation. Conclusions  The spatial variability of characterization factors between provinces is in the same order of magnitude as the overall range between chemicals for aquatic acidification while much smaller for photochemical ozone formation. Hence, at this stage of knowledge, province-based regionalization seems to be more relevant for the aquatic acidification impact category than for photochemical ozone formation. Recommendations and perspectives  Research must be pursued to integrate a better transport and deposition model with improved spatial capabilities and a successive modeling step properly describing the cause–effect chain up to the damage level, such as the biotic environment and the human population.     

制作竹类秆箨标本的新方法

秆箨作为鉴别竹类植物重要的营养器官 ,自然脱落后易卷或易破碎。常规的压制方式所制作的腊叶标本通常质量都不高 ,这给竹种的鉴定带来很大的困难。本文介绍一种新的秆箨腊叶标本制作方法 ,即熨斗熨烫法 ,并就这种方法对秆箨性状所产生的影响作了客观分析 ,结果表明 :它对保存秆箨分类性状有很大的改进 ,对标本质量有明显的提高     

一种提取小鼠表皮总RNA的新方法

目的:建立一种从小鼠表皮组织提取高质量RNA的方法。方法:用热击法分离小鼠表皮,用TRIzol法提取RNA,用紫外分光光度计测定RNA的产率和纯度,用琼脂糖电泳和RT-PCR检测RNA的质量和完整性。结果:采用新方法提取的小鼠表皮总RNA,其D260nm/D280nm值为1.8～2.0,大于1.5,且RNA产率高于100μg/g;琼脂糖电泳出现5S、18S和28S等3条清晰的rRNA条带,而且28SrRNA条带的亮度约为18S的2倍;用新方法制备的总RNA可成功地用于RT-PCR实验。结论:采用热击法分离表皮并结合TRIzol法可提取到高质量、完整性好的小鼠表皮总RNA,并能用于相关的分子生物学实验。     

一种早期胚胎体外培养新方法的建立

建立一种不依赖于液体石蜡的早期胚胎体外培养方法——套皿法,并比较了4种不同处理方法体外培养胚胎的效果。结果显示,采用套皿法进行胚胎培养,盖液体石蜡和不盖液体石蜡皿中的胚胎在各阶段的发育率差异不显著。与套皿法相比,用单皿微滴覆盖法(Brinster法)培养的胚胎在各阶段的发育率显著降低。不覆盖液体石蜡单皿中的胚胎则阻断于二细胞阶段。实验设计的套皿法是一种有效的早期胚胎体外培养方法,为早期胚胎体外培养提供了一种新方法。     

一种用于观察纤毛虫表膜下结构的扫描电镜样品制备新方法

该实验摸索出通过扫描电镜观察纤毛虫表膜下三维结构的新方法:用适当浓度的KMnO_4作为固定剂,固定虫体细胞表膜,调整固定液的渗透压使细胞在低渗溶液中胀破、细胞质溶出,表膜剥落下来、内外翻转,经脱水、冷冻干燥、喷金后,在扫描电镜下对爽口虫(Climacostomumsp.)、尾草履虫(Paramecium caudatum)及拟尾柱虫(Paraurostyla weissei)的表膜下结构进行了观察。结果表明:利用此方法能够观察到表膜下层次分明而又清晰的三维立体构象。此方法可为纤毛虫表膜及其它细胞质膜的研究提供可借鉴的样品制备新方法。     

A Rapid Method of Isolation and Fractionation of Proteoglycans Using a Vertical Tube Rotor for Isopycnic Centrifugation

A comparison was made between a vertical tube rotor and a fixed angle rotor for isopycnic centrifugation of proteoglycans. In the vertical tube rotor, isopycnic gradient was achieved much faster than in the conventional fixed angle rotor. The use of a vertical tube rotor for isopycnic centrifugation shortens the time considerably for the isolation of proteoglycans fron various tissues.     

A New Isolation Method for Labyrinthulids Using a Bacterium, Psychrobacter phenylpyruvicus

A new isolation method for labyrinthulids, marine microbes with spindle-shaped vegetative cells and gliding movement, is presented. The method for isolating labyrinthulids has been found to be more difficult and less reproducible than that for thraustochytrids, classified in the same order. So far serum seawater agar fortified with antibiotics has been proposed to be the best for isolation of labyrinthulids. The method presented here involves placing plant samples on an agar medium on which a marine bacterium, Psychrobacter phenylpyruvicus, has been grown. The new method, which utilizes fallen mangrove leaves as source material, was more than twice as effective as isolation agar medium without the bacterium. The increased effectiveness appears to derive partly from the bacterial colonies' delaying extension of fungal mycelium. The bacterium was more effective for the isolation of labyrinthulids than either the bacterium Shewanella sp. or the yeast Rhodotorula rubra.     

A New Method for Self-Regulation of Slow Cortical Potentials in a Timed Paradigm

A new method of slow cortical potential (SCP) biofeedback is described, in which subjects were presented with a sequence of two alternating tones. Subjects learned to adjust their SCPs with the 4-s rhythm of presented tones by producing directed SCP changes only in certain inter-tone intervals. Specifically, they learned to simultaneously produce two EEG signals: 1) positive or negative SCP shift at vertex, and 2) SCP asymmetry between the right and the left central area. After one training session, 13 healthy participants were able to differentiate significantly between the negativity and the positivity conditions; this differentiation was achieved within less than 300 ms after the discriminative signal, i.e. much faster than in previous studies employing traditional SCP biofeedback technique. However, these participants did not produce a significant hemispheric asymmetry in the first session. In the second experiment, five subjects participated in prolonged training (6 to 17 sessions). Highly significant control of SCP asymmetry over the precentral cortex was attained in four out of five participants. Advantages and disadvantages of the new method as compared with the classical SCP biofeedback technique are discussed.     

用质量控制狭缝式杂交法（Coslot）检测妇女宫颈上皮中人乳头瘤病毒（HPV）DNA

本文报道一种能对ＨＰＶ进行较为准确分型的刚Ａ杂交程序和方法。它具有如下特点：１．由于简化了实验程序,标本消耗减少。因此该方法尤其适用于小组织活检标本（１－２ｍｇ）中ＤＮＡ同源序列检测;２．敏感性高。由于标本消耗减少,使ＨＰＶ检出率大为提高,与斑点杂交技术相比,敏感性提高１．６倍;３．型别特异性强。由于改变了实验条件及在实验过程中实行严格的质量控制,明显减少了不同ＨＰＶ型别的交叉反应,甚至在部分出现交叉反应的标本中,仍可通过强度对比来最后判定ＨＰＶ感染型别。应用该技术对１４３份宫颈炎标本、１７份宫颈不典型增生标本及２５份宫颈癌标本进行了ＨＰＶ１６型检测,阳性率分别为５０．０５％（７３／１４３）、５７％（２７／４７）及７６％（１９／２５）,并与Ｄｏｔｂｌｏｔ方法进行了比较。该方法在ＨＰＶ感染与宫颈癌关系的分子流行病学研究中具有重要意义和广阔的应用前景。     

A New Simple Method for Isolating Multistress-Tolerant Semidominant Mutants of Saccharomyces cerevisiae by One-Step Selection under Lethal Hydrogen Peroxide Stress Condition

A tetrathionate-decomposing enzyme that catalyzes the decomposition of tetrathionate into thiosulfate and sulfate was purified to homogeneity from tetrathionate-grown Thiobacillus thiooxidans. The enzyme had an apparent molecular weight of 104,000, and was composed of two identical subunits (MW = 58,000) as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme had an isoelectric point at 9.6 and was most active at pH 3.0–3.5 and 40°C. Enzyme activity was increased approximately 100-fold in the presence of 400 mm sulfate ion. The Michaelis constant of this enzyme for tetrathionate in the presence of 20, 50, and 200 mm of sulfate ion was 2.4 mm. Mercuric and ferric ions completely inhibited the enzyme activity at 1 mm. Though cupric ion up to 0.01 mm markedly stimulated the activity in the presence of 20 mm sulfate ion, a higher concentration (1 mm) rather strongly inhibited the activity. Ethylenediaminetetraacetic acid (EDTA) strongly inhibited the activity, but this inhibiton was completely restored by cupric ion.     

A New Spectrophotometric Method for the Detection of Lipase Activity Using 2,4-Dinitrophenyl Butyrate as a Substrate

A rapid and sensitive assay for the detection of lipase activity is described. The method is based upon the increase in absorbance at 360 nm due to the formation of the 2,4-dinitrophenolate anion during the enzymatic hydrolysis of 2,4-dinitrophenyl butyrate. The substrate is used in an emulsified form. Using a diode array spectrophotometer with internal referencing a correction can be made for absorbance changes due to clearance of the emulsion during hydrolysis. The small reaction volume and the high extinction coefficient of the product makes the method applicable for detection of both low substrate and low enzyme concentration.

Four lipases were tested: lipase from porcine pancreas, Candida cylindracea, Pseudomonas sp. and Aspergillus niger. All enzymes are readily able to catalyse the hydrolysis of 2,4-dinitrophenyl butyrate.     

A New Monte Carlo Method for Direct Calculation of the Critical Size and the Formation Work of a Microdrop

New Monte Carlo procedures in open ensembles are proposed. Non-stationary Markov chain procedure in the μl;pT - ensemble provides a direct estimation for the critical size of a condensation nucleus at given p and T. A stationary procedure in the μlpT ensemble with two allowed particle numbers n and n + 1 provides the direct way to calculate the chemical potential and Gibbs free energy of a cluster; in the grand canonical (μlVT) ensemble the same approach gives μl and the Helmholtz free energy. The same procedures are readily applicable to periodic systems representing bulk phases.     

A New Method for Inoculation of Poor Germinator, Nosema sp. NIS M11 (Microsporida: Nosematidae), into an Insect Cell Culture

ABSTRACT. Spores of Nosema sp. NIS M11, primed with 0.1 N KOH solution, were mixed with either physiological salt solutions or IPL-41 medium, an insect cell culture medium, for germination. In the latter medium, only a few spores germinated, while high percentages of spore germination were obtained in physiological salt solutions, particularly in Rinaldini's solution. By using the salt solutions as inoculation media, KOH-primed NIS M11 spores were inoculated into the Spodoptera frugiperda SF21AEII cell line. The initial infection levels were consistently higher than that obtained by using IPL-41 medium. Among the salt solutions, Rinaldini's solution, containing KCl in place of NaCl, gave the highest percentage of initial cell infection. Increased osmolarity of salt solutions did not improve the efficiency of spore germination and infection of N. sp. NIS M11.     

A New Method for Locating Changes in a Tree Reveals Distinct Nucleotide Polymorphism vs Divergence Patterns in Mouse Mitochondrial Control Region

A new, model-based method was devised to locate nucleotide changes in a given phylogenetic tree. For each site, the posterior probability of any possible change in each branch of the tree is computed. This probabilistic method is a valuable alternative to the maximum parsimony method when base composition is skewed (i.e., different from 25% A, 25% C, 25% G, 25% T): computer simulations showed that parsimony misses more rare → common than common → rare changes, resulting in biased inferred change matrices, whereas the new method appeared unbiased. The probabilistic method was applied to the analysis of the mutation and substitution processes in the mitochondrial control region of mouse. Distinct change patterns were found at the polymorphism (within species) and divergence (between species) levels, rejecting the hypothesis of a neutral evolution of base composition in mitochondrial DNA. Received: 15 March 1999 / Accepted: 7 October 1999     

A New Method for Studying <Emphasis Type="Italic">in vitro</Emphasis> Lipid Transport: The 45-kDa Protein from Rat Olfactory Epithelium Is a Specific Carrier of Phosphatidylinositol 3,4,5-Triphosphate

A new method for studying lipid-protein interactions in vitro is developed. It enables the study of the transporting activity of a protein toward a lipid ligand, including the case of an unknown lipid type. The method can be considered as a variant of partition three-phase chromatography with two stationary (donor and acceptor) phases and one mobile phase. The protein under study is dissolved in an aqueous mobile phase and induces a specific delivery of a lipid to the acceptor lipid layer. The transported lipid is identified in Folch lipid extracts from the acceptor layer and aqueous phase. The secretory protein with M 45 kDa from the rat olfactory epithelium is shown to be a carrier of phosphatidylinositol 3,4,5-triphosphate. Our approach opens up new possibilities in the study of lipid-protein interactions in vitro and has a number of advantages over the methods now used for these purposes.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 4, 2005, pp. 445–448.Original Russian Text Copyright ¢ 2005 by Radchenko, Shuvaeva, Il’nitskaya, Tret’yakov, Lipkin.